Development of 3D electrodes for improved electrochemical production of hydrogen


Due to global warming and the pressing challenges of climate change, the interest in renewable energy sources has risen rapidly. However, the increasing production of these intermittent energy sources causes problems regarding the electrical net, as it is not designed to deal with alternating periods of overproduction and periods of shortage. In order to solve this problem, a system of energy storage can be integrated in the electrical net. In this way, the net load can be balanced and a further expansion of the capacity of renewable energy production is allowed, without causing intermittency problems.

Both redox flow batteries and hydrogen form interesting opportunities to be employed as energy carriers. Since the use of hydrogen does not create emissions, its carbon footprint is dependent of its origin. Therefore, a carbon neutral cycle can be created when instead of employing conventional fossil feedstocks to produce grey hydrogen, water electrolysis in combination with renewable electricity is used to produce green hydrogen.

However, with current prices of 2.5 to 5.5 €/kg, green hydrogen is far more expensive than grey hydrogen which only costs 1.5 €/kg. A major factor herein is the power usage, which determines 80% of the green hydrogen price. In order to lower the power usage, research focus typically lies on improving the electrocatalyst, while reactor engineering remains underdeveloped. With this PhD project I will tackle this knowledge gap and investigate how structured 3D electrodes can improve the performance of water electrolysers. With the combined effect of a high surface area and structured geometry, a reduced ohmic resistance, an efficient bubble release, a small pressure drop and a uniform current distribution can be obtained, tackling the power usage of today’s water electrolysers. Through 3D printing and the use of coating techniques such as electrodeposition, the influence of the electrode geometry and surface structure on the efficiency losses in water electrolysers will be characterised, yielding insight in parameters such as the ohmic resistance, hydrodynamic properties and bubble release size.